Heat exchanger

ABSTRACT

A heat exchanger is provided. The heat exchanger includes a tube through which a refrigerant flows, a fin disposed on an outer periphery of the tube, and an agitating member inserted into the tube, and agitating the refrigerant.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchanger, and moreparticularly, to a refrigerant tube structure of a heat exchanger thatimproves heat exchange efficiency by increasing a contact area between aliquid refrigerant flowing through a refrigerant tube and an innerperiphery of the refrigerant tube.

2. Description of the Related Art

In general, a fin-tube type heat exchanger used in an air conditioner orthe like includes a refrigerant tube having the shape of a meander linewhich is curved a plurality of times, and a plurality of heat exchangefins inserted into the refrigerant tube in a direction that the heatexchange fins are intersected with the refrigerant tube.

The related art fin-tube type heat exchanger acts as an evaporator or acondenser in such a way that a refrigerant exchanges heat with externalair while the refrigerant flowing through the refrigerant tube.Specifically, a heat exchange area between the refrigerant and theexternal air is increased by means of the heat exchange fins which areinserted into the refrigerant tube and arranged close to each other.Thus, a heat exchange is effectively performed.

In addition, grooves are formed on an inner periphery of the refrigeranttube of the fin-tube type heat exchanger for improving heat exchangeefficiency. Here, the grooves are spirally formed such that they areconnected in a longitudinal direction of the refrigerant tube.

In virtue of the grooves, when the heat exchanger is used as anevaporator, the contact area between the liquid refrigerant and therefrigerant tube is increased, and thus the heat exchange efficiency isimproved. Besides, when the heat exchanger is used as a condenser, thecontact area between the vapor refrigerant and the refrigerant tube isincreased so that the heat exchanger having the grooves is advantageousin improving the heat exchange efficiency.

Meanwhile, when the heat exchanger having the related art refrigeranttube is used as the evaporator, the liquid refrigerant flows at anoutlet portion of the refrigerant tube. When the heat exchanger is usedas the condenser, the liquid refrigerant flows at an inlet portion ofthe refrigerant tube. Such a refrigerant flows along a bottom surface ofthe refrigerant tube due to gravity.

Specifically, when the related art heat exchanger having theabove-described refrigerant tube is used as an evaporator, the liquidrefrigerant flows into the inlet of the evaporator. Therefore, thecontact area between the refrigerant and the inner periphery ofrefrigerant tube is decreased at the inlet of the evaporator, and thusthe heat exchange efficiency of the heat exchanger is degraded. That is,there is a drawback that the refrigerant is not completely vaporizedbecause the degree of superheat of the evaporator is lowered.

Moreover, when the heat exchanger is used as a condenser, the liquidflows through the outlet of the condenser. Accordingly, the contact areabetween the liquid refrigerant and the inner periphery of therefrigerant tube is decreased at the outlet of the condenser, and thusthe heat exchange efficiency of the heat exchanger is degraded. That is,there is a drawback that the refrigerant is not completely liquidizedbecause the degree of supercooling of the condenser is lowered.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a heat exchanger thatsubstantially obviates one or more problems due to limitations anddisadvantages of the related art.

An object of the present invention is to provide a heat exchanger thatimproves heat exchange efficiency by increasing a contact area between arefrigerant and an inner periphery of a refrigerant tube at an inlet ofthe refrigerant when the heat exchanger is used as an evaporator.

Another object of the present invention is to provide a heat exchangerthat improves heat exchange efficiency by increasing a contact areabetween a refrigerant and an inner periphery of a refrigerant tube at anoutlet of the refrigerant when the heat exchanger is used as acondenser.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein,there is provided a heat exchanger, including: a tube through which arefrigerant flows; a fin disposed on an outer periphery of the tube; andan agitating member inserted into the tube, and agitating therefrigerant.

In another aspect of the present invention, there is provided a heatexchanger, including: a tube; a fin contacting the tube to be thermallyin contact with an external air; and an agitating member spiraled aplurality of times for increasing a contact area between a liquidrefrigerant and an inner periphery of the tube, the agitating memberbeing provided inside the tube.

When the heat exchanger according to the present invention is used as anevaporator, a contact area between a liquid refrigerant and an innerperiphery of the refrigerant tube at an inlet of the evaporator isincreased. Thus, it is possible to increase heat exchange efficiency.

In addition, when the heat exchanger according to the present inventionis used as condenser, a contact area between a liquid refrigerant and aninner periphery of the refrigerant tube at an outlet of the condenser isincreased. Thus, it is possible to increase heat exchange efficiency.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a perspective view of a heat exchanger according to the presetinvention;

FIG. 2 is a sectional view of a refrigerant tube according to arefrigerant tube;

FIG. 3 is an exploded perspective view illustrating a connection of therefrigerant tube according to the present invention;

FIG. 4 is a partially sectional perspective view taken along line I-I ofFIG. 3; and

FIG. 5 is a graph of experimental data illustrating a performancecomparison result of a related art heat exchanger and the heat exchangeraccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

FIG. 1 is a perspective view of a heat exchanger 1 according to thepresent invention.

Referring to FIG. 1, the heat exchanger 1 according to the presentinvention includes a refrigerant tube 10 through which a refrigerantflows, heat exchange fins 20 penetrated by the refrigerant tube 10 andarranged at regular distances, and an agitating member 30 inserted intothe refrigerant tube 10.

Specifically, the heat exchange fin 20 is formed from a thin plate withhigh thermal conductivity and is attached on an outer periphery of thetube 10, thereby increasing a heat exchange area between the refrigerantand an air current S and thermal conductivity.

FIG. 2 is a sectional view of the refrigerant tube 10 according to arefrigerant tube.

Referring to FIG. 2, a plurality of protrusions 13 are formed on aninner periphery of the refrigerant tube 10 in spiral shape.

In detail, the protrusions 13 are formed such that they scrape along theinner periphery of the refrigerant tube 10 in a spiral direction. Theseprotrusions 13 play a role in improving heat transfer capability byincreasing a contact area with the refrigerant tube 10 when therefrigerant flows through the refrigerant tube 10.

The agitating member 30 having a helical shape is inserted into therefrigerant tube 10. Specifically, the agitating member 30 changes theflow of the refrigerant flowing through the refrigerant tube 10 so thatthe contact area between the refrigerant and the inner periphery of therefrigerant tube 10 is increased.

That is, the flow of the refrigerant flowing through the refrigeranttube 10 is changed into turbulent flow from laminar flow, whichincreases the contact area between the refrigerant and the refrigeranttube 10.

FIG. 3 is an exploded perspective view illustrating a connection of therefrigerant tube 10 according to the present invention, and FIG. 4 is apartially sectional perspective view taken along line I-I of FIG. 3.

Referring to FIG. 3, the refrigerant tubes 10 of the heat exchanger 1according to the present invention is prepared such that a plurality ofU-shaped pipes are mutually connected to each other by a return band 11.The agitating member 30 is inserted into an end of the refrigerant tube10.

Here, the agitating member has a length extending from one end of therefrigerant tube 10 to the other end from which a curvature starts.Therefore, turbulence phenomenon does not occur due to the flow of therefrigerant in a state that the agitating member 30 is inserted into therefrigerant tube 10.

Referring to FIG. 4, the agitating member 30 according to the presentinvention is shaped such that a rim-shaped member with a predeterminedwidth and thickness T is spirally wound.

In detail, the spirally shaped agitating member 30 is formed in theshape of a spring having a predetermined inner diameter D1 and apredetermined outer diameter D2.

In more detail, it is preferable that the inner diameter D1 of theagitating member 30 be 25-40% of an inner diameter D3 of the refrigeranttube 10 in consideration of flow resistance of the refrigerant and thecontact area between the liquid refrigerant and the inner periphery ofthe refrigerant tube 10.

In other words, when the diameter D1 of the agitating member 30 is lessthan 25% of the inner diameter D3 of the refrigerant tube 10, thecontact area between the liquid refrigerant and the refrigerant tube 10is increased and a flow resistance of the refrigerant is increased aswell. Therefore, the heat exchange capability of the heat exchanger 1 isdegraded.

On the contrary, when the inner diameter D1 of the agitating member 30is greater than 40% of the inner diameter D3 of the refrigerant tube 10,the flow resistance of the refrigerant is decreased and the contact areabetween the liquid refrigerant and the refrigerant tube 10 is alsodecreased, which causes the heat exchange capability of the heatexchanger 1 to be degraded.

In addition, in consideration of a contact area between the protrusions13 formed in the refrigerant tube 10 and the flow resistance of therefrigerant, it is preferable that the outer diameter D2 of theagitating member 30 be 95% or less of the inner diameter D3 of therefrigerant tube 10.

That is, when a diameter D2 of the agitating member 30 is greater than95% of the diameter D3 of the refrigerant tube 10, the contact areabetween the refrigerant and the protrusion 13 is increased but the flowresistance of the refrigerant is also increased, whereby the heatexchange capability of the thermal exchanger 1 is degraded.

In addition, to reduce the flow resistance of the refrigerant, it ispreferable that a distance P between pitches of the agitating member 30be greater than the inner diameter D3 of the refrigerant tube 10 atleast.

Preferably, the agitating member 30 having the above shape is insertedinto an inside portion of the refrigerant tube 30 through which theliquid refrigerant flows.

In other words, a vapor refrigerant can contact the inner periphery ofthe refrigerant tube 10 with ease but the liquid refrigerant isgenerally in contact with a bottom portion of the refrigerant tube 10due to its own viscosity and gravity. Thus, it is preferable that theliquid refrigerant flowing through the refrigerant tube 10 contacts theinner periphery of the refrigerant tube 10 to increase a heat exchangearea.

Specifically, when the heat exchanger 1 is used as an evaporator, abinary phase refrigerant that has undergone an expansion procedure flowsinto an inlet of the evaporator. Since the amount of liquid refrigerantis more than the amount of vapor refrigerant at the inlet of theevaporator, it is preferable that the agitating member 30 be provided tothe inlet of the evaporator.

Contrariwise, when the heat exchanger 1 is used as a condenser, a vaporrefrigerant with high pressure and temperature that has passed through acompressor flows into an inlet of the condenser, and a liquidrefrigerant with high temperature flows into an outlet of the condenserthrough condensation procedure. Accordingly, it is preferable that theagitating member 30 be provided to the outlet of the condenser.

Thereinafter, the performance of the heat exchanger 1 having theabove-mentioned structure will be described with reference to a graphshowing experimental data.

FIG. 5 is a graph of experimental data illustrating a performancecomparison result of a related art heat exchanger and the heat exchangeraccording to the present invention.

Referring to FIG. 5, when the heat exchanger 1 is used as an evaporator,a low temperature liquid refrigerant flows into the inlet of theevaporator, and is heat-exchanged with an external air while it flowingthrough the refrigerant tube 10 so that the low temperature liquidrefrigerant is changed into a low temperature vapor refrigerant. Indetail, the liquid refrigerant flowing through the refrigerant tube 10absorbs the heat of the air current S transferred through the fin 20.Therefore, the low temperature liquid refrigerant is changed into thevapor refrigerant and the vapor refrigerant then flows out through theoutlet of the evaporator. The heat of the air current S is transferredto the refrigerant, and thus the air becomes cool.

Meanwhile, it was confirmed that the heat of evaporation of theevaporator employing the inventive refrigerant tube 10 having theagitating member 30 is increased to 101.7% assuming that the heat ofevaporation of the related art heat exchanger be 100%. That is, when theheat exchanger 1 having the refrigerant tube structure according to thepresent invention is used as the evaporator, it was understood from FIG.5 that the heat exchanger absorbs more heat, i.e., about 1.7%, from theair current S in comparison with the related art evaporator, and thusits heat exchanging capability is improved.

In addition, when the heat exchanger 1 is used as a condenser, a hightemperature vapor refrigerant flows into an inlet of a condenser, and ischanged into a high temperature liquid refrigerant while it flowingthrough the refrigerant tube 10. That is, after the heat of the vaporrefrigerant is released into the air current S through the fins 20 sothat the vapor refrigerant is changed into the liquid refrigerant, theliquid refrigerant flows out through the outlet of the condenser.

Furthermore, it was confirmed from FIG. 5 that the heat of condensationof the condenser employing the inventive refrigerant tube 10 isincreased to 102.7% assuming that the heat of condensation of therelated art heat exchanger be 100%. That is, when the heat exchangerhaving the refrigerant tube structure according to the present inventionis used as the condenser, it was understood that the heat exchangerrelease more heat, i.e., about 2.7%, into the air current S incomparison with the related art evaporator, and thus its heat exchangingcapability is improved.

As described above, according to the present invention, the amount ofheat exchange of the refrigerant with the external air can be increasedby inserting the agitating member 30 into the refrigerant tube 10,because the agitating member 30 increases the contact area with theinner periphery of the refrigerant tube by changing the flow of therefrigerant.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present invention. Thus,it is intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A heat exchanger comprising: a tube through which a refrigerantflows; a fin disposed on an outer periphery of the tube; and anagitating member inserted into the tube, and agitating the refrigerant.2. The heat exchanger according to claim 1, wherein the agitating memberhas a helical shape.
 3. The heat exchanger according to claim 1, whereinthe agitating member is disposed in a section where a liquid refrigerantflows.
 4. The heat exchanger according to claim 1, wherein a distancebetween pitches of the agitating member is greater than an innerdiameter of the tube.
 5. The heat exchanger according to claim 1,wherein a plurality of protrusions are formed on an inner periphery ofthe tube.
 6. The heat exchanger according to claim 1, wherein theagitating member is provided in a linear section of the tube.
 7. A heatexchanger comprising: a tube; a fin contacting the tube to be thermallyin contact with an external air; and an agitating member spiraled aplurality of times for increasing a contact area between a liquidrefrigerant and an inner periphery of the tube, the agitating memberbeing provided inside the tube.
 8. The heat exchanger according to claim7, wherein the agitating member is curved in a direction different froma flow direction of a refrigerant.
 9. The heat exchanger according toclaim 7, wherein an outer diameter of the agitating member is 95% orless of an inner diameter of the tube.
 10. The heat exchanger accordingto claim 7, wherein an inner diameter of the agitating member is 25%˜40%of an inner diameter of the tube.
 11. The heat exchanger according toclaim 7, wherein the agitating member is provided to an outlet of thetube when a refrigerant passing through a compressor flows into thetube.
 12. The heat exchanger according to claim 7, wherein the agitatingmember is provided to an inlet of the tube when the refrigerantundergoing an expansion procedure flows into the tube